---
url: >-
  https://adk.nht.io/api/@nhtio/adk/batteries/variables/E_ISOLATE_FUNCTION_ARG_UNSUPPORTED.md
description: >-
  Thrown when an `invoke()` argument contains an exotic leaf (a
  function/Error/custom-encodable) that `codec.ts`'s tiered encoder would need
  to escalate past the `'raw'` tier. The isolated Blob guest has no module
  imports (by design — no bare specifiers survive a Blob URL) and therefore
  cannot load `@nhtio/encoder` to decode an `enc: 'nhtio'` value;
  `isolateFunction` only ever supports plain, structured-cloneable arguments.
  Non-fatal: a caller can pass different, plain arguments instead.
---

# Variable: E\_ISOLATE\_FUNCTION\_ARG\_UNSUPPORTED

```ts
const E_ISOLATE_FUNCTION_ARG_UNSUPPORTED: CreatedException<[string]>;
```

Defined in: [src/batteries/isolation/isolate\_function.ts:103](https://github.com/NHTIO/ADK/blob/v1.20260713.1/src/src/batteries/isolation/isolate_function.ts#L103)

Thrown when an `invoke()` argument contains an exotic leaf (a function/Error/custom-encodable) that
`codec.ts`'s tiered encoder would need to escalate past the `'raw'` tier. The isolated Blob guest has
no module imports (by design — no bare specifiers survive a Blob URL) and therefore cannot load
`@nhtio/encoder` to decode an `enc: 'nhtio'` value; `isolateFunction` only ever supports plain,
structured-cloneable arguments. Non-fatal: a caller can pass different, plain arguments instead.